The effects of metallic Si addtions on the synthesis of β-SiC powders using a sol-gel method

Single phase (β-SiC powders were synthesized using Si0₂/C hybrid precursors with and without the addition of metallic SI powders. The SICVC hybrid precursors with various C/SI mole ratios (1.6-4.0) were prepared by a sol-gel process using tetraethyl orthosilicate and phenol resin as starting materials. Fine (β-SiC powders were synthesized by the carbothermal reduction of the SICVC hybrid precursor with and without the addition of metallic SI powders in the temperature range between 1250 C-1800 °C under a vacuum atmosphere. Single phase (β-SiC powders were obtained by the carbothermal reduction of the SICVC hybrid precursor with a C/SI mole ratio of 1.6 above 1600 °C under a vacuum atmosphere. It was found that the addition of metallic SI powders to the the SICVC hybrid precursor with excess carbon reduced the temperature for the synthesis of single phase [β-SiC powders to as low as 1350 °C. The particle sizes of synthesized (β-SiC powders from the metallic SI powder added SICVC hybrid precursor with excess carbon were less than 1 fan, in which fine β-SiC powders appeared to be slightly aggregated.